Porteus

Here is a place for your projects which are not officially supported by the Porteus Team. For example: your own kernel patched with extra features; desktops not included in the standard ISO like Gnome; base modules that are different than the standard ISO, etc...

For converting videos there is the famous ffmpeg, but without GUI.
Winff is a good GUI for ffmpeg but limited in options.
For Microsoft Windows there is MediaCoder a powerful tool to work with multiple video formats.
MediaCoder is functional in gnu/linux through wine.
I've done some tests here and this tool is working very well.